20.05.2008
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11:00 - 11:15
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Opening
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11:15 - 12:00
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Frank Schreiber
Tübingen
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Do we understand the binding of molecules at surfaces?
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Abstract anzeigen
The lecture will give an introduction to understanding the binding of molecules to surfaces. The method of standing x-ray waves for the precise determination of bond distances will be explained. Case studies including (strong) chemisorption, mere physisorption as well as the wide range in between will be discussed with reference to the following publications:
Adsorption induced intramolecular dipole: Correlating molecular conformation and interface electronic structure. F. Schreiber et. al., J. Am. Chem. Soc., in print.
Impact of bidirectional charge transfer and molecular distortions on the electronic structure of a metal-organic interface. F. Schreiber et. al., Phys. Rev. Lett.2007, 99, 256801.
Adsorption-Induced Distortion of F16CuPc on Cu(111) and Ag(111): An X-ray Standing Wave Study. F. Schreiber et. al., Phys. Rev. B2005, 71, 205425.
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12:00 - 12:45
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Luisa de Cola
Münster
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Application of Molecular Switches
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13:00 - 15:00
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Lunch
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15:00 - 15:45
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Falk Renth
Kiel
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Ultrafast Spectroscopy: Techniques and Applications
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Abstract anzeigen
Since the discovery and commercial availability of self mode-locked titanium-sapphire (Ti:Sa) pulsed lasers, time-resolved spectroscopy with ultrashort (femtosecond) laser pulses has attracted considerable research interest in biophysics and physical chemistry. The short duration of the pulses allows the study of chemical reactions on the time scale of the underlying molecular structural changes, thus providing fundamental insight into the mechanisms and molecular dynamics. In this talk a brief overview of the fundamentals of ultrafast spectroscopy will be presented. Following an introduction to ultrashort pulse generation, the properties and the non-linear optics of femtosecond laser pulses, important pump-probe techniques for time-resolved spectroscopy such as transient absorption and fluorescence up-conversion will be described. The application of these methods will be illustrated by several examples, including the ultrafast dynamics of photochromic molecular switches.
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15:45 - 16:30
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Tobias Brixner
Würzburg
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Spectroscopy and Control of Complex Quantum Systems
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Abstract anzeigen
Ultrafast spectroscopy is widely used for studying time-resolved quantum phenomena, and active manipulation ("control") is also possible using shaped femtosecond laser pulses. With increasing complexity of the investigated systems the experimental challenges rise drastically, requiring new approaches. Several novel spectroscopy and control techniques and applications to complex systems will be presented. For example, coherent two-dimensional spectroscopy can be used to measure electronic couplings directly and follow energy transport through space and time with nanometer and femtosecond resolution. On the other hand, coherent control technology has been successfully transferred from the gas phase to liquid-phase conditions. It is now possible to control chemical bond-breaking reaction channels and to obtain macroscopic amounts of product substances, for example via an accumulative scheme for ultrasensitive femtochemistry. Other directions of research use quantum control as a sophisticated spectroscopic tool to extract wave-packet dynamics and information on Hamiltonians. Finally, it is possible to incorporate ultrafast nano-optics and achieve subwavelength control of electromagnetic fields and forces as shown in simulations as well as recent experiments. The prospects of "nano-femto" spectroscopy will be discussed by which one could directly map energy transport with ultrafast time resolution and far below the diffraction limit of conventional light fields.
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16:30 - 17:00
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Coffee Break
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17:00 - 18:00
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Phillipp Gütlich
Mainz
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Spin state switching in iron complexes - From molecular processes to possible applications
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Abstract anzeigen
Coordination compounds of transition metal ions with open-shell electron configurations may exhibit dynamic electronic structure phenomena, depending on the nature of the coordinating ligand sphere. Thermal, light- and pressure-induced changes of spin states [1-5] are among the most fascinating electronic games encountered in transition metal compounds, which are presently under extensive study by chemists and physicists. The switching properties make such material potential candidates for practical applications in thermal and pressure sensors as well as optical devices.
The basics of thermal and optical spin transition will be briefly reviewed. Selected examples of thermal spin crossover in mono-, oligo- and polynuclear iron(II) complexes will be discussed, with special emphasis on the importance of cooperative interactions. It will be shown that switching forth and back between different spin states may be effected by irradiation with light of different wave lengths ("Light-Induced Excited Spin State Trapping (LIESST)"). The effect of pressure on the spin transition behavior will be demonstrated. New activities towards synthesis of systems exhibiting synergic effects, like spin state switching and liquid crystalline properties, are briefly outlined. Possible practical applications will be discussed.
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18:00 - 19:00
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Rainer Herges
Kiel
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Organic Photochemistry
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Abstract anzeigen
Photochemistry is a typical interdisciplinary science. The interaction of light with matter is studied in chemistry, physics, biology and medicine. Organic chemists are mainly interested in applications aimed at the synthesis of chemical compounds. The basic principles of organic photochemistry will be presented and demonstrated with experiments.
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19:00
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Dinner
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21.05.2008
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08:00 - 09:00
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Breakfast
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09:00 - 09:45
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Daniel Bürgler
Jülich
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Spintronics: Spin Dependent Transport in Magnetic Multilayers
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Abstract anzeigen
Since the discovery of interlayer exchange coupling and giant magnetoresistance (GMR) in the 1980's spin-dependent transport in magnetic multilayer and nanostructures has attracted a lot of interest. The research was motivated by applications -i.e. GMR read- heads in computer harddisks and the magnetic random access memory (MRAM)- as well as exciting new phenomena, which nowadays constitute the research field called spintronics. The fast-paced development of spintronics culminated in the award of the Nobel Prize in Physics 2007 for the discovery of the GMR effect. I will highlight the historical development of spintronics and review interlayer exchange coupling, giant and tunneling magnetoresistance (GMR, TMR), and current-induced magnetization dynamics as the major novel phenomena of spintronics. For each of them I will introduce a comprehensible physical picture and discuss realized and potential applications.
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09:45 - 10:30
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Henning Menzel
Braunschweig
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Azobenzene-Containing Polymers for Surface Relief Gratings
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Abstract anzeigen
Azobenzene-containing polymers have attracted much interest in applications for data storage and other optical technologies. This wide range of applications arises from the unique phenomena found for these materials: Upon exposition to polarized light dichroism and birefringence can be induced. When azobenzene containing polymer films are irradiated with interference patterns of polarized light surface relief gratings (SRG) on the micrometer-scale can be observed. (...) view full text (PDF)
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10:30 - 11:00
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Coffee Break
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11:15 - 12:00
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Richard Berndt
Kiel
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Scanning Tunnelling Microscopy
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Abstract anzeigen
A brief introduction to scanning tunnelling microscopy and spectroscopy will be given. Emphasis will be put on molecular systems and contact experiments.
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12:00 - 12:45
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Héctor Vázquez
Lyngby
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Modeling band alignment at organic semiconductor interfaces
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Abstract anzeigen
The aim of this talk is to present an overview of the theoretical understanding of energy level alignment properties at interfaces of organic materials. The talk will focus on issues such as molecular level offsets and injection barriers involving low-weight organic molecules. The physical mechanisms that take place at such interfaces and their theoretical description will be explained, focusing on Density-Functional Theory-based approaches. Several examples will be discussed, in order to provide a better understanding of the power and limitations of first-principles methods in organic semiconductor interfaces.
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12:45 - 14:30
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Lunch
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14:30 - 15:15
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Kai Roßnagel
Kiel
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Photoemission from adsorbed molecules
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Abstract anzeigen
Modern condensed matter and surface physics benefit from various sophisticated and highly refined photoemission techniques including angle-resolved photoemission spectroscopy (ARPES), inverse photoemission spectroscopy (IPES), photoelectron diffraction (PhD), photoemission electron microscopy (PEEM), and X-ray standing wavefield absorption (XSW). A crash course in these experimental techniques will be given, in the course of which the potentials and limitations will be discussed with particular reference to the question: What can we hope to learn from photoemission about the electronic and geometric structure of adsorbed molecules and the nature of the chemical bonds between substrate and adsorbate?
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15:15 - 16:00
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Thomas Strunskus
Kiel
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XPS, NEXAFS and IRRAS: Fundamentals and Examples
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Abstract anzeigen
An introduction will be given to the surface analytical techniques x-ray photoelectron spectroscopy (XPS), near edge x-ray absorption fine structure spectroscopy (NEXAFS) and infrared reflection absorption spectroscopy (IRRAS). XPS provides semiquantitative information on the chemical composition of the sample (elements and oxidation states) and it can be also used to determine the thickness of thin layers and to obtain shallow depth profiles (both in the nm range). NEXAFS can be used to get information on the electronic structure of molecules and on the orientation of molecules in thin adsorbate films. IRRAS provides information about the orientation and the chemical status of thin adsorbate layers. Selected examples relevant to the topic of the SFB will be presented for all three methods.
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16:00 - 16:30
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Coffee Break
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16:30 - 17:15
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Martin Beyer
Kiel
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Single Force Spectroscopy with the Atomic Force Microscope (AFM)
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Abstract anzeigen
The basic principle of AFM is introduced, and the standard operating modes for imaging of surfaces with atomic resolution are briefly discussed. Single molecule force spectroscopy is the investigation of mechanical properties of single molecules, from the folding/unfolding behavior of polymers to the stretching and breaking of covalent bonds. Recent examples from the original literature are presented, including the optomechanical cycle of a molecular switch.
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17:15 - 18:00
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Round Table
Discussion
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Expertise and Deficiencies in our SFB (Chemistry, Physics, Materials)
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18:00
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Closing Remarks
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